A device for vehicle transmissions for the maneuvering of a vehicle clutch typically comprises the following components: a clutch release lever carried in the gearbox and cooperating with a throwout bearing which, in turn, actuates the clutch itself. The clutch release lever generally has two shanks which bear on engagement surfaces on the throwout bearing. The clutch is generally rotatably arranged on the same shaft as a flywheel while a clutch disc is pressed against the flywheel by a pressure plate which is spring-biased by a diaphragm spring. The pressure plate, in turn, is operated by the throwout bearing by means of the diaphragm spring. It is known to utilize a vehicle clutch having a pulling throwout bearing cooperating with a clutch release lever which is fastened on a rotatable axle. In clutches having pulling throwout bearings, the bearing is directly coupled to the clutch mechanism and, thus, to the engine, while the axle having the clutch release lever is carried in the gearbox housing. This division creates problems when joining the gearbox to the engine, for example in connection with repairs, when the gearbox has to be mounted onto an engine already installed in the vehicle. The problems are created by the fact that the shanks of the clutch release lever will have to be rotated in behind the engagement surfaces of the throwout bearing at the same time as the input shaft of the gearbox is inserted into a center of the clutch disc and a guiding sleeve is inserted into the throwout bearing. The rotating movement of the lever axle will then have to be coordinated with the axial displacement of the gearbox, which is difficult because the throwout bearing and the lever are hidden by a clutch bell-housing when they are in position for beginning such engagement. Thus, the mechanic cannot perform this synchronization in other ways than to feel his/her way without seeing the relative positions of the components.
According to Swedish Patent No. 451,211, a rotatable axle is carried in a clutch bell-housing using two fulcrum points. A clutch release lever is fastened to the axle and cooperates with a throwout bearing. By rotating the axle, the bearing will be subjected to a pulling force in the direction of disengagement by means of the lever. An intercepting device is connected with the bearing in order to catch the shanks of the lever, during joining of the gearbox to the engine, and to steer the ends of the lever into engagement with engagement surfaces of the throwout bearing. The intercepting device is formed by a brace made of spring steel. Because the clutch has been provided with an intercepting device, it is sufficient if the mechanic places the lever in a predetermined, downwardly angled mounting position. When the gearbox is then slid into place, the lever is automatically steered to the proper position behind the engagement surfaces of the throwout bearing. This construction is stable and provides a guaranteed operation, but it has the disadvantage that it cannot compensate for misalignment of the axle and mounting errors regarding the relative positions of the gearbox and engine. The consequence may be an uneven distribution of forces in the lever, which will result in increased wear and functional disturbances.
Alternative solutions to the problem associated with guiding the lever during mounting of a gearbox onto an engine, also called docking, have been proposed. They all have in common that they utilize some type of throwout bearing having a catch. The throwout bearing is installed temporarily on the input shaft of the gearbox, with the clutch release lever in its operating position, so that it is automatically fixedly snapped onto the diaphragm spring of the clutch during assembly. These solutions are distinguishably more expensive, and have an inferior reliability than the solution according to Swedish Patent No. 451,211.
In order to compensate for misalignment of the clutch release lever, the lever may be spherically carried in an axial uniball bearing. According to U.S. Pat. No. 4,860,870, the clutch release lever is mounted at a support point which has a cylindrical support surface which cooperates with a corresponding support surface on the clutch release lever. This arrangement is claimed to compensate for the misalignment which may occur during assembly or operation. These axial uniball bearings allow for limited movement in all directions, i.e. they cannot rotate a full revolution about any axis, which results in the lever not being capable of being angled sufficiently to allow for docking according to Swedish Patent No. 451,211. Therefore, a docking procedure according to the above described solution is required where a throwout bearing having a catch is utilized.